Whether you are somebody who is injured and looking to learn a movement which will correct the malfunctions causing the injury, or whether you are injury free and simply looking to learn a new exercise, you need to have an idea of the volume and rep range per set you should be working with.
The first thing you need to be aware of is that learning the feel of the movement plays far more importance than simply striving to get an arbitrary number of repetitions in a set. This plays especially true if you are learning the exercise to help overcome an injury as it is likely you have never properly felt the correct muscles working before. If you are to move correctly in future, you need to learn what each part of the body feels like when it is in correct position at each part of the range. Practising a movement with this in mind helps you feel when you have moved out of correct position, creating an awareness of your own body position within space without needing to see yourself move or have someone observe you.
The next important thing to consider is rep speed. You will hear a lot of people say that exercises should mimic real-life movements and, since we don’t move in slow motion in daily life or sports, then exercises should not be performed in slow motion either. Whilst we agree with that sentiment, once good technique has been mastered, it is always better to start learning a new exercise by keeping the rep speed slow. This is because it takes time to get the feel of all the new positions you should put your body into and it takes time to think about where you need to move to as you travel through the range of the movement. Moreover, if you have a group of muscle fibres which are underactive and untrained (but need strengthening to get the technique right), the neural-muscular pathways will be untrained and slow to send the nervous impulses to get those fibres firing. By taking your time on each rep, it buys those motor units time to activate those underactive areas. The slow speed also gives the right muscles more time under tension and, in effect, can provide as much extra volume of training work as increasing the number of reps.
The least most important thing to mention in an article on the number of sets and reps for learning a new exercise is precisely the number of sets and reps! The main rule is to keep the number of reps per set at 5 or fewer. Low reps mean that more intense mental focus can be put on concentrating on getting the positions and feel of the new exercise correct. It also allows for more sets to be performed, where each set can be viewed as a new opportunity to work on improving something lacking in the previous set. In terms of how many sets to do, it is best to stop when you feel you are tiring to the point you can no longer achieve the correct positions you are striving for with the new exercise. The newer the movement is to you, the more likely you are to tire after only a few sets. Add more sets as you improve over time.
If people put half as much effort into learning how to do their exercises properly as they do into thinking about set and rep schemes, they would be in a much better position. Sets and reps really aren’t as important as people give them credit for and yet, for some people, it’s the only thing they think about.